The compound (.+-.)-2-methylpiperidine has a high degree of specificity in enhancing the binding of nicotine in the rat brain (Sloan, J. W. et al., J. Med. Chem. 1985, 28, 1245); specifically, the (+)isomer of (.+-.)2-methylpiperidine enhances the binding of nicotinic ligands to rat brain receptor sites (Sloan, J. W. et al., Life Sci. 1985, 37:1367). However, neither of these Sloan et al references suggests that (+)-2-methylpiperidine affects cerebral circulation or cognitive function. It has now been found that (+)-2-methylpiperidine has the ability to enhance nicotinic neurotransmission, either alone or by co-administration with a known nicotinic agonist. This finding has enabled a therapeutically-useful agent having diminished potential side-effects to be produced.